Fluid fuel burner



ug. l, 1933. R. F. BRUNS FLUID FUEL BURNER Filed OCT.. 19, 1931 awww/Hozm R B E R Patentedl Aug. 1, 1933 l .UNITED STATES PATENT OFFICE FLUIDFUEL BURNER i Robert F. Bruns, Sarpy County, Nebr.

Application October 19, 1931.l Serial No. 569,705

2 Claims. (Cl. 158-28) My invention relates to burners for fluid saidhub 11 and resting upon the bottom of the fuels, such as gas and oil,wherein the fuel is dedraft-tube, and a pair of collar-portions 14arlivered from a nozzle into a stream of air moving ranged symmetricallyat opposite sides of the axially of the nozzle, and wherein the fuel ishub above the fuel-pipe. The collar-portions mixed with the air, ignitedand burned in a zone 14 are kerfed and provided at the kerfs with 50adjacent to the nozzle. It is the object of my clamp-screws 15 forholding therein the insulatinvention to provide, for burners of theforegoing-sleeves 16 which surround the stem-portions ing character, acombined electrical ignition 17 of the ignition-electrodes. Said stems17 are and air-directing device whereby the ignition parallel with eachother, being held by the supl electrodes may be positioned outside thepath of port and the insulating sleeves 16 in positions 65 the fuelemerging from the nozzle, and the arc intermediate the fuel-pipe and thesides of the 0r succession of sparks which pass between the draft-tube,at a level above the fuel-pipe and electrodes be carried by a deiiectedportion of the nozzle. To the outer or front end 0f the the air-streaminto the path of the fuel to igstems 1'7 are connected suitablyinsulated connite the same. A further object is to provide ductors 18which are extended through the 70 means for effecting a whirling ortwisting motion draft-tube alongside the fuel-pipe to connect of theperipheral portion of the air-stream withwith the coil, transformer orother source of out interfering with the directing of that parthigh-tension Current emplOI/'ed f01` the ignitionof the air-stream whichcarries the ignition arc The rear end of one of the electrodes is curved20 into contact with the fuel. laterally as shown in Fig. l, andslightly down- In the accompanying drawing Fig. 1 is a plan ward asshown in Fig. 2, so that the end of the view of devices embodying myinvention, the electrode is above and extends slightly beyond associateddraft-tube being in horizontal section, the end Of the DOZZle, Said end0f the eleCtlOde Fig. 2 is a side view, the draft-tube being inverhaving a flat horizontal terminal edge 19 extical section, and Fig. 3is an end view of the tending transversely t0 the aXiS 0f the HOZZle 80device. and draft-tube. The rear end portion of the In the illustratedembodiment of my invention other electrode is bent laterally,substantially at the same is applied to an oil burner wherein the aTight angle aS SllOWn in Fig- 1, tO eXtend fuel-nozzle 5 is Carried atthe end of a pipe 6 transversely in spaced relation to the end 19 ofthrough which the oil is supplied under pres the first electrode, thetransverse terminal porsure, the nozzle having at the end thereof a,tion being flattened to form a substantially recsmall central aperturethrough which the fuel tanglllal" plate 20 Which iS inCliIled, aS ShOWIlin emerges in e, conical Spray, The fueppipo eX- Fig. 2, so that itslower edge is rearward of its tends longitudinally within a much largerpipe upper edge 90 or draft-tube 7, through which the air is Sup- In theoperation of the described burner, the plied for supporting combustionof the fuel, the fuel is sprayed from the nozzle in a conical forairusually being under forced draft, being immatlOn, aS indicated in Fig.2, and the Outer pelled by a fan or bloweisuch as is Commonly portion ofthe air-stream through the draftemployed in this art. The draft-tube isextendtube ls given a Whll'llng 01' tWlStlng motion by 95 ed through thewall 3 of o, furnace to the comthe helical ribs 10 in the annular space`about bustion-chamber thereof, said tube terminating the mouth 0f Saidtube- The Central pOltlOn 0f at or near the inner side of said wall, andthe the alt-Stream tends t0 InOVe along Paths Sub' fuel-pipe beingarranged so that the nozzle 5 is Stantally parallel With the eXiS 0f thenOZZle, near the end of the drafttubo but does not but at the end of thenozzle the air-stream forms project therefrom, an eddy about thetransverse end-surface there- Preferably, there is disposed within therear 0f, and the feel-jet or spray also tends to enor inner end of thedraft-tube a sleeve 9 having train and dmW lOOTtlOnS 0 the all' 1ntOWafd foi-med integrally therewith a plurality 0f he1 the axis thereof.iThe flat transversely extend- 5 cal ribs 10 adapted to @auge o, whiningmotion ing inclined terminal-plate 2() intercepts a porof the air-streamemerging thciefrom. Within tion 0f the air-Stream and dlleCtS the Samethe draft-tube, and spaced forwardly or outdownwardly tOWind theSpray-0ne 0f tl1e fuel, Wardly from the end ofthe Sleeve 9y is a Supandsaid deflected portion of the air-stream port comprisingr a hub-portion11 tting upon passes between said plate 20 and the terminal the fue1pipe and secured thereto by a Screw 12y edge 19 of the other electrode.Said deflected a leg-portion 13 extending downwardly from portion of theair-stream causes the arc, o1 succession of sparks passing between theterminals 19 and 20, to assume a U-shaped formation, bowing downwardlyfrom the terminals and contacting with the spray-cone of the fuel toeffectively ignite the same. The gap or distance between the terminals19 and 20 is so proportioned that the initial spark or electricaldischarge is readily formed between the same, and the potential of theignition-current employed is such that after the initial discharge orbreakdown of the gap the path of the alternating arc or series of sparkspassing between the electrodes may be greatly elongated and assume thedeeply bowed U-formation represented in Fig. 2, before disruption of thearc will occur.

It will be seen that by the described structure the ignition electrodesare relatively distant from the path of the fuel and cannot contact withor become fouled thereby, or accumulate carbon deposits which mightshort-circuit and render the same inoperative. The Wide endface 19 ofthe one electrode and the plate 20 of the opposed electrode affordrelatively large areas-between which the ignition arc may pass, so thatpitting or erosion of a portion of the surface will not alter the widthof the gap as a whole nor prevent normal continuation of the ignition.

In burners of this class it appears to be necessary, or highlydesirable, to provide means for producing a whirling or twisting motionof the main body of the air-stream emerging from the draft-tube aboutthe fuel-nozzle, such motion of the air-stream causing a more rapid andeffective mixing of the air and fuel, and greatly reducing the roaringnoise caused during operation of the burner. The usual means forproducing the twisting movement of the air-stream, comprises helicoidalblades or vanes positioned within the draft-tube forwardly of thefuelnozzle and relatively distant from the end or mouth of thedraft-tube, so that all of the air passing the nozzle is disturbed anddeflected by such air-directing means. In my improved structure, thehelical ribs 10 on the sleeve 9 in the mouth of the draft-tube, producethe desired whirling motion of the air and quiet operation of theburner, although said ribs aifect directly only the outer or peripheralportion of the airstream, and thus avoid interference with the directingof the central portion of the air-stream to produce the desired bowedformation of the ignition arc.

Now, having described my invention, what I claim and desire to secure byLetters Patent is:

1. In a uid fuel burner, the combination with a fuel-nozzle adapted todeliver a jet of fuel, and a draft-tube surrounding said nozzle andadapted to direct an air-stream longitudinally past the same; ofignition-electrodes disposed adjacent to said nozzle and having wideterminal portions spaced apart longitudinally of the draft tube andextending transversely thereof, the forward of said transverse terminalportions having a face at the gap between the electrodes inclined to thedraft-tube axis, and said inclined face being positioned to deflect aportion of the air-stream through the gap and toward the fueljet, forthe purpose set forth.

2. In a fluid fuel burner, the combination wit a draft-tube provided atthe discharge mouth thereof with annularlyl arranged helicalair-directing means, and a fuel-nozzle arranged centrally of said mouthin spaced relation to said air-directing means; of ignition-electrodesdisposed adjacent to said nozzle and having wide terminal portionsspaced apart longitudinally of the draft-tube to provide a gap betweenthem, the forward of said terminal portions being shaped and arranged todirect air through said gap toward the orifice of the nozzle.

ROBERT F. BRUNS.

